[Real-time RT-PCR based on DNA subtraction for absolute quantification of gene expression in engineered lactic acid bacteria].

To evaluate the absolute quantification of a target gene transcription in engineered lactic acid bacteria, we developed the Real-time RT-PCR based on DNA subtraction. We isolated the total RNA from the bacteria samples by glass bead, and then analyzed the Ct data of real-time RT-PCR by DNA subtraction assay. Using this method, we successfully estimated the expression level of CBHII gene in the strain of genetic engineered Lactococcus lactis. Since this method could avoid the mRNA copy number loss, it could be used to estimate the expression of other genes in lactic acid bacteria.